A NSW Parliamentary Inquiry has heard that were only two ambulances serving the entire Blue Mountains.

But Blue Mountains MP Trish Doyle and an ambulance insider said the situation was sometimes worse, when ambulances get "trapped in bed block at Nepean Hospital ... there's nothing here".

The matter was raised by Upper House Labor MP Walt Secord on February 1. He asked Nepean Blue Mountains Local Health District chief executive Kay Hyman whether she was "surprised" that there were just two ambulances for 80,000 people. Ms Hyman's response was "I don't have those numbers, so I can't comment". Last week the Gazette was told Ms Hyman would not be making further comment, as it was a matter for the ambulance service.

In a statement on Monday the ambulance service said across a 24-hour period there were a minimum of 28 ambulances available in the Nepean Blue Mountains zone. This covers Penrith, Colyton, Warragamba, Richmond, Springwood and Katoomba.

The spokesperson said the state government had "invested more than $9 billion in NSW Ambulance since 2011, including $1.4 billion in the 2021/22 budget" and "in the event of a medical emergency, the closest available paramedics are always dispatched to patients, with life-threatening injuries and illnesses triaged as a priority".

But an ambulance insider said: "Every day [in the Mountains] there are four transport vehicles and at night there are only two." A special ops crew also worked rescues.

"Within an hour of the [day] shift, Springwood tend to get sucked into the Nepean catchment, a rapidly growing area ... then one of the Katoomba crews get sucked to cover Springwood. There are odd days where you have a quiet day where they stay where they started. When they drain resources ... and the shit hits the fan ... there's nothing here."

When asked whether the area is adequately resourced, the insider said "it wasn't and it won't be in the future". But from next week a record number of juniors would start and be paired with a senior staff member. The insider said it was a "knee jerk" reaction to the Omicron variant.

Ms Doyle said "every Mountains resident should feel concerned, if not outraged, that the NSW government only financially supports one ambulance per 40,000 residents".

"If both ambulances are trapped in bed block at Nepean Hospital there's actually no ambulance coverage. In this pandemic crisis, every single graduated paramedic should be employed permanently with the accompanying ambulance fleet to address the need not currently met."

The insider said there were quite a few incidents where tragedy had occurred because an ambulance was more than 45 minutes away in Penrith.

A Productivity Commission report, released this month, shows the NSW ambulance service lags behind the nation on resourcing, response times and community coverage.

"We spend less, have fewer paramedics on the road, and patients wait longer," Australian Paramedics Association (NSW) president Chris Kastelan said

"NSW has Australia's second worst paramedic to population ratio, with just 48.6 paramedics per 100,000 people, per capita ... a third fewer paramedics than Queensland and Tasmania."

The report also showed median emergency response times (12.5 minutes) were Australia's second-slowest.

"The likelihood of survival for a cardiac event can drop by 10 per cent for each minute treatment is delayed."